CBM CBM Inhalation Injury & Respiratory Management 1 — Questions and Answers
Question 1: Which clinical finding is the most reliable early indicator of inhalation injury in a burn patient?
- Singed nasal hairs and eyebrows (Correct answer)
- Peripheral cyanosis
- Low SpO2 on pulse oximetry
- Audible wheezing
Correct answer: Singed nasal hairs and eyebrows
Singed nasal hairs, carbonaceous sputum, and facial burns are the most reliable clinical signs of inhalation injury even before respiratory distress develops.
Question 2: Why is standard pulse oximetry unreliable in patients with carbon monoxide (CO) poisoning?
- It overestimates oxygen saturation because it cannot distinguish oxyhemoglobin from carboxyhemoglobin (Correct answer)
- It underestimates saturation due to skin discoloration
- CO interferes with the infrared LED
- It only measures venous oxygen
Correct answer: It overestimates oxygen saturation because it cannot distinguish oxyhemoglobin from carboxyhemoglobin
Pulse oximetry reads carboxyhemoglobin as oxyhemoglobin, falsely reporting near-normal saturations in the presence of significant CO poisoning.
Question 3: What is the first-line treatment for carbon monoxide poisoning in a burn patient?
- 100% high-flow oxygen via non-rebreather mask (Correct answer)
- Hyperbaric oxygen immediately
- Nebulized bronchodilators
- IV sodium bicarbonate
Correct answer: 100% high-flow oxygen via non-rebreather mask
High-flow 100% oxygen reduces the half-life of carboxyhemoglobin from ~5 hours on room air to approximately 60–90 minutes.
Question 4: Subglottic inhalation injuries typically result from which mechanism?
- Inhalation of superheated steam or toxic chemical gases (Correct answer)
- Direct flame contact to the face
- Thermal burns below the vocal cords from dry hot air
- Aspiration of liquid smoke
Correct answer: Inhalation of superheated steam or toxic chemical gases
Steam carries much more heat energy than dry air and can transfer that heat below the glottis, causing subglottic injury, while dry air is usually cooled by the upper airway.
Question 5: When should early prophylactic intubation be considered in an inhalation injury patient?
- Signs of stridor, hoarseness, or progressive facial and oropharyngeal edema (Correct answer)
- SpO2 below 95% on room air
- Presence of carbonaceous sputum alone
- Any patient with burns over 10% TBSA
Correct answer: Signs of stridor, hoarseness, or progressive facial and oropharyngeal edema
Airway edema can progress rapidly and occlude the airway; early intubation before complete obstruction is far safer than emergent intubation after obstruction.
Question 6: Which ventilation strategy is recommended for inhalation injury patients to prevent ventilator-induced lung injury?
- Low tidal volume (6 mL/kg IBW) with permissive hypercapnia (Correct answer)
- High tidal volume to maximize CO2 clearance
- High PEEP with tidal volumes of 10–12 mL/kg
- Pressure-controlled ventilation at high rates
Correct answer: Low tidal volume (6 mL/kg IBW) with permissive hypercapnia
Lung-protective ventilation using low tidal volumes (6 mL/kg IBW) limits barotrauma and volutrauma in the damaged, non-homogeneous inhalation-injured lung.
CBM CBM Inhalation Injury & Respiratory Management 1
Which clinical finding is the most reliable early indicator of inhalation injury in a burn patient?